The present invention relates to a rotary brush specifically designed for motor vehicle washing systems.
As is known, automatic motor vehicle washing systems conventionally comprise washing brush elements.
Prior rotary brush elements generally comprise a support, of cylindric configuration, and coupled to a rotary member.
On the outer surface of the support element are applied a plurality of flexible cleaning elements, adjoining one another and coupling, at an end portion, to said support element, orthogonally thereto.
The automatic cleaning and washing of the motor vehicle body are achieved by causing a plurality of brushes of the above disclosed type to properly rotate, to cause their flexible elements, held in a preset configuration under the effect of the centrifugal force generated by the rotary brushes, to impact the motor vehicle body, through the interposition of water and/or suitable washing solutions or emulsions.
The above mentioned prior cleaning elements, in particular, are at present made of a polyethylene material, in the form of wires, or they comprise felt materials, in the form of strips or bands.
In the first case, the free end portion of each brush forming wire is crushed, with a specifically designed method called “feathering”, to increase the width of each said wire, to distribute its impact pressure on a larger surface, while increasing the cleaning surface.
On this end portion which, after the above mentioned treatment, as a set rough and porosity, minute particles, either of stone or metal nature, are deposited, said particles being collected from the previously cleaned surfaces.
The removed particles enter the mentioned rough and porous parts, to be crusted therein, thereby forming abrading regions which can scratch the paint of the motor vehicle being washed, and generate minute scorings thereon.
This same drawback also occurs, in a further enhanced manner, if felt elements are used, which felt material, of spongy nature, is susceptible easily embed the abrading particles therein.
Moreover, with felt cleaning elements, since the felt materials have a great liquid absorption properties, a further drawback occurs that, at a temperature near to zero, and because of a cooling effect caused by the evaporation generated by the washing brush movement, the elements tend to fully or partially freeze, thereby stiffening and preventing the washing system from properly operating.
The washing brush elements made of band elements, comprise a plurality of strips or strings, which are formed by partially cutting through the band elements.
Said strips are arranged perpendicularly to the axis of the entraining shaft, thereby said bands are restrained.
This constructional solution generates a series of problems.
In fact, to provide a suitable cleaning surface, it is necessary to perform the assembling of sectors or bristles supporting strips with a close arrangement, to prevent an uneven washing action from occurring.
In prior washing brushes, if the bristle supporting sectors or strips are spaced, in the spaced surface portions, the brush bristles will have gaps negatively affecting the cleaning of some regions of the motor vehicle body.
Moreover, if conventional band elements are arranged at a close spacing from one another, they provide undesired bridgings or overlappings of the strips, with a consequent possibility of an early wear of adjoining band strips.
Moreover, to provide even washing characteristics, it is necessary to mount on the supporting shaft a plurality of band supporting sectors or strips arranged in a close relationship and, to that end, it is necessary to use a supporting shaft of a suitable size to mechanically resist against the stress induced by the mentioned band elements.
Thus, because of the above mentioned over-sizing, the washing brushes will have a comparatively large weight, with a large increase of the consumed power, a greater wear of the rotary members and, accordingly, an increasing of the washing system faults.
Moreover, prior rotary brushes, including a plurality of close arranged bands, can damage the motor vehicle antenna and rear windows.
To the above it is to be added that the above mentioned band elements are frequently made of a foamed material and are affixed to the supporting shaft by several types of connecting means such as rivets, small bars and so on.
For technical reasons, the number of said band elements can vary from a minimum number to a number which is from one to three times larger and, as stated, the arrangement of the side surface of the shaft can be either too close or too spaced apart.
Then, as the thus designed washing brush is rotatively driven, the distribution of the strings cut through the band elements will mirror the arrangement of said band elements on the inner cylinder.
All the tradeoffs related to a lacking of space on the surface of the tube or supporting shaft are reflected mirror-like on the side surface of the thus formed cylindric brush.
However, as in regions of the washing brush is provided to use a minimum amount of band elements, the latter, which are affixed by conventional insert members, cannot be arranged with a rational arrangement on the washing cylinder.